000
FXUS62 KILM 020545
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
145 AM EDT SUN AUG 2 2015
.SYNOPSIS...
A WEAK FRONT WILL REMAIN STALLED ACROSS THE COASTAL CAROLINAS...
PRODUCING ISOLATED SHOWERS AND THUNDERSTORMS NEAR THE COAST. THE
FRONT SHOULD DISSIPATE ON MONDAY. BERMUDA HIGH PRESSURE WELL
OFFSHORE WILL BUILD WESTWARD THIS WEEK. TEMPERATURES WILL REMAIN
SEASONABLE TO SLIGHTLY ABOVE NORMAL THROUGH THE WEEKEND INTO NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1000 PM SATURDAY...FORECAST SOUNDINGS FROM BOTH THE NAM AND
GFS SHOW A THIN LAYER OF UNSTABLE AIR AT THE TOP OF TODAY`S DEEP
MIXED LAYER ACROSS THE PEE DEE REGION. THIS IS NOT A SITUATION I
WOULD HAVE ANTICIPATED CONVECTION TO DEVELOP WITHIN GIVEN ELEVATED
INSTABILITY BASED AROUND 6500 FEET AGL AND BONE-DRY AIR AT AND
ABOVE 700 MB. NEVERTHELESS THERE ARE SHOWERS WITH LOCALLY HEAVY
RAIN DEVELOPING ALONG THE I-95 CORRIDOR FROM FLORENCE NORTHWARD TO
NEAR BINGHAM IN WESTERN DILLON COUNTY. INFRARED SATELLITE SHOWS
ADDITIONAL MID- LEVEL CLOUD COVER EXTENDING NORTHWARD INTO ROBESON
COUNTY NC...SO I HAVE TO AT LEAST CONSIDER THE POSSIBILITY FOR
SHOWERS TO DEVELOP THIS FAR NORTH AS WELL.
AT THE SURFACE HIGHER DEWPOINTS HAVE RETURNED WESTWARD INTO THE
INTERIOR COASTAL PLAIN WITH 70S SHOWING UP AGAIN IN LUMBERTON...
MARION AND FLORENCE. THIS MOISTURE MAY BE TOO THIN TO BE FEEDING
THE CONVECTION DIRECTLY...AS THE SURFACE IS LIKELY DECOUPLED FROM
THE ATMOSPHERE ALOFT.
LATEST HRRR MODEL RUNS DO NOT REALLY SHOW THIS CURRENT ACTIVITY
WELL...ALTHOUGH INTERESTINGLY THE 00Z NAM DOES. THE NAM MOVES THE
SHOWERS EASTWARD TOWARD THE COAST...DISSIPATING THE CONVECTION
BETWEEN 06-09Z NEAR MYRTLE BEACH.
AT 500 MB THE CAROLINAS FORM THE BASE OF A BROAD TROUGH EXTENDING
DOWN FROM HUDSON BAY CANADA. PLENTY OF DRY AIR AT AND ABOVE 700 MB
SHOULD CONTINUE ON WESTERLY WINDS OVERNIGHT. HIGH PRESSURE OVER
THE OHIO VALLEY WILL DRIFT EASTWARD INTO THE CENTRAL APPALACHIANS
SUNDAY MORNING. THIS WILL NUDGE OUR FRONT OFF THE COAST INTO THE
NEARSHORE WATERS BY DAYBREAK. MOISTURE TRAPPED WITHIN THE
DECOUPLED BOUNDARY LAYER WILL REMAIN TRAPPED OVERNIGHT...AND WITH
GOOD RADIATIONAL COOLING I ANTICIPATE PATCHY FOG WILL
DEVELOP...ESPECIALLY EAST OF I-95 WHERE DEWPOINTS ARE HIGHEST.
LOWS SHOULD FALL 70-74...WARMEST AT THE BEACHES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...STATIONARY FRONT WILL REMAIN IN AREA
SUNDAY BEFORE DISSIPATING IN PLACE ON MONDAY. MEANWHILE...A
BROAD...FLAT-ISH H5TROUGH WILL REMAIN ANCHORED IN PLACE OVER
EASTERN CONUS. GUIDANCE STILL SHOWING PLENTIFUL DRY AIR ALOFT
WHICH WILL LIMIT EXTENT OF CONVECTION DESPITE PRESENCE OF FRONTAL
BOUNDARY AND THE OCCASIONAL SHORT WAVE THAT WILL DROP INTO THE
BASE OF THE UPPER TROUGH. AIR ALOFT IS DRIEST INLAND...SO WILL
SHOW A DECREASING GRADIENT IN POPS NW FROM THE COAST FOR BOTH
DAYS. DUE TO OVERALL LIMITED MOISTURE ALOFT...WILL KEEP POPS
CAPPED AT LOW CHANCE FOR THE IMMEDIATE COAST FOR BOTH DAYS...WITH
FAR INLAND AREAS BEING POSSIBLY TOO DRY TO SEE ANY SIGNIFICANT
RAINFALL.
TEMPERATURES WILL REMAIN ABOVE CLIMO THROUGH THE SHORT TERM AND
HEAT INDEX VALUES WILL LIKELY REACH AROUND A 100 OR SO BOTH
AFTERNOONS. HOWEVER...HEAT ADVISORY CRITERIA IS NOT EXPECTED TO
BE EXCEEDED.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...WHAT LITTLE MOISTURE THERE WILL BE IN
PLACE ON TUESDAY WILL BE POOLED UP ALONG THE COAST. MINOR RAIN
CHANCES WILL BE FOCUSED THERE DURING AN OTHERWISE HOT AFTERNOON
PROVIDED IN PART BY A VERY WEAK RIDGE ALOFT. RAIN CHANCES REMAIN
SLOW ON WEDNESDAY AS THE FLOW ALOFT STAYS WEAK THOUGH THE SENSE OF
RIDGING WEAKENS. SO WILL KEEP POPS MINIMIZED BUT SHOW THEM AREA-
WIDE. RAIN CHANCES RAMP UP TO SCATTERED ON THURSDAY AS SOME WEAKLY
CYCLONIC CURVATURE OVERSPREADS THE REGION AND A SURFACE PIEDMONT
TROUGH TAKES SHAPE. ANOTHER LITTLE PIECE OF ENERGY WILL PROVIDE
SOME LIFT ON FRIDAY WHICH MAY BE ANOTHER FAIRLY ACTIVE DAY. ON
SATURDAY NOT ONLY WILL THERE BE CONTINUED DISTURBANCES IMPINGING
UPON THE AREA FROM THE NORTHWEST BUT A COLD FRONT WILL ALSO BE
MOVING INTO THE CAROLINAS. WEDNESDAY AND THURSDAY WILL BOTH SEE
RATHER HOT AFTERNOONS WHEREAS THE INCREASE IN CLOUDS LATE IN THE
PERIOD SHOULD TEMPER THINGS A BIT BACK TOWARDS CLIMO.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...EARLIER CONVECTION HAS DISSIPATED ACROSS THE CWA AND
SKIES HAVE TRENDED CLEAR FOR THE MOST PART. WITH SUFFICIENT LOW-
LEVEL MOISTURE...AN INVERSION AND LIGHT WINDS...PATCHY FOG
IS FORECAST ACROSS THE INLAND TERMINALS WITH MVFRVSBY BETWEEN
09-12Z. MAIN WEATHER FEATURE FOR TODAY WILL BE THE STATIONARY
FRONT/SEA BREEZE WHICH WILL TRIGGER ISOLATED SHOWERS OR TSTMS
ACROSS THE COASTAL TERMINALS THIS AFTERNOON AND EVE. WILL KEEP VFR
AT ALL THE TERMINALS...BUT CANNOT RULE OUT BRIEF MVFRVSBY/
CEILING IF CONVECTION OCCURS DIRECTLY OVER KILM/KCRE/KMYR.
EXTENDED OUTLOOK...PREDOMINANTLY VFR THROUGH THE PERIOD WITH A
SLIGHT CHANCE AFTERNOON SHRA/TSRA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM SATURDAY...A FRONT IS STALLED ACROSS THE COASTAL
PLAIN OF THE CAROLINAS THIS EVENING. HIGH PRESSURE OVER OHIO WILL
DRIFT EAST INTO THE CENTRAL APPALACHIANS LATE TONIGHT. THIS SHOULD
NUDGE THE FRONT EASTWARD AND INTO THE COASTAL WATERS LATE. SOUTH
TO SOUTHWEST WINDS THIS EVENING AS HIGH AS 15 KNOTS IN THE CAPE
FEAR AREA SHOULD DIMINISH TO LESS THAN 10 KNOTS AFTER
MIDNIGHT...THEN TURN NORTHWESTERLY LATE AS THE FRONT PUSHES OFF
THE COAST.
THE PRIMARY WAVE SET IS A 7-SECOND SOUTHERLY SWELL...WITH A
SMALLER 10-SECOND SOUTHEASTERLY SWELL SHOWING UP. THESE TWO WAVES
WILL CONTINUE INDEPENDENT OF THE WIND OVERNIGHT...WITH COMBINED
SEAS 2-4 FEET...HIGHEST OFFSHORE FROM CAPE FEAR.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A STALLED FRONT WILL DISSIPATE OVER THE
EASTERN CAROLINAS ON MONDAY AS BERMUDA HIGH PRESSURE OFFSHORE
EXTENDS BACK WEST ACROSS THE WATERS. WINDS WILL SETTLE BACK INTO A
SWLY DIRECTION BY SUNDAY NIGHT AS THE FRONT WEAKENS AND
DISSIPATES. A SMALL CRAFT ADVISORY MAY BE REQUIRED MONDAY
AFTERNOON OR EVENING AS THE GRADIENT TIGHTENS WITH HIGH PRESSURE
BUILDING WEST ACROSS THE WATERS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...WIND AND SEAS RELAX ON TUESDAY AS
PIEDMONT TROUGHINESS PUSHES THE TIGHTER GRADIENT CAUSED BY THE
BERMUDA HIGH FURTHER OUT TO SEA. THOUGH SOME SWELL ENERGY MAY
REMAIN WE SHOULD DROP BELOW ADVISORY THRESHOLDS. THEREAFTER IT
LOOKS LIKE PRETTY STANDARD FARE FOR JULY WITH A SOUTHWESTERLY WIND
IN THE 10 TO 15 KT RANGE AND 2 TO 4 FTSEAS...HIGHEST OFFSHORE.
&&
.TIDES/COASTAL FLOODING...
AS OF 200 AM SATURDAY...MINOR COASTAL FLOODING IS POSSIBLE DURING
THE NIGHT-TIME HIGH TIDE OVER THE NEXT COUPLE OF DAYS. THESE
HIGHER THAN NORMALTIDES ARE THE RESULT OF THE PERIGEAN SPRING
TIDE AND A FULL MOON WHICH OCCURRED ON FRIDAY. DEPARTURES OF PLUS
1/2 TO 1 FOOT WILL BE ENOUGH TO PRODUCE A BRIEF PERIOD OF MINOR
COASTAL FLOODING. THE RISK IS HIGHEST FOR PORTIONS OF THE LOWER
CAPE FEAR RIVER TO INCLUDE DOWNTOWN WILMINGTON...WITH A LIKELYPROBABILITY. THE BEACHES WILL APPROACH THE THRESHOLD FOR MINOR
COASTAL FLOODING AGAIN THIS EVE...BUT THIS WILL BE THE LAST TIME
THIS LUNAR CYCLE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...REK
LONG TERM...MBB
AVIATION...MAC/RJD
TIDES/COASTAL FLOODING...RJD